The present disclosure relates generally to backlights having a light input wedge where a specularly reflective surface is adjacent to the light input wedge side surfaces but not in intimate contact with the light input wedge.
Optical devices employing backlights are used, for example, in displays for laptop computers, hand-held calculators, digital watches, cell phones, televisions and similar devices as well as illuminated signs and many other devices.
Light can be supplied to backlights via optical elements that can include conventional reflectors. Conventional reflectors, including, silvered mirrors, polished metallic or metallized surfaces where the reflective surface is in optical or intimate contact with the wedge, etc., suffer from a number of disadvantages in many applications. For example, these conventional reflectors suffer from relatively high absorbance of light incident on their surfaces, often absorbing about 10% of the light incident on them. As a result, the amount of light remaining after each reflection is less than that initially provided. In devices in which multiple reflections are encountered, the overall output of the optical device can be substantially limited.